This invention relates to ostomy products, i.e., appliances and apparatus to be used by colostomy patients. Medical patients who have contracted colon disease such as cancer must frequently undergo radical colostomy surgery, which results in removal of a substantial amount of the lower intestine and resulting formation of a surgically implemented waste outlet through the abdominal wall, called a "stoma." Such patients must then wear a specially designed pouch-like container, typically of thin, flexible plastic sheet material, which mounts over the stoma to receive and collect body eliminations. Typically, this pouch is releasably attached to a patch-like mounting member called the "appliance," which is adhesively secured to the patient in a secure manner over the stoma and has an opening communicating with the latter. Usually, the patient-mounted "appliance" has a ring-like attachment member, and the pouch has a complementary ring-like portion defining a pair of spaced annular walls which snap over the ring on the appliance to thereby secure the pouch to the appliance in a leak-proof manner. Each such ring-like member has a large central aperture through which eliminated body waste passes to enter the pouch.
One problem which arises in use of such apparatus is the accumulation of gas within the pouch, which inflates the latter in an undesirable manner and may cause leakage or even rupture, etc. The basic practice for dealing with this problem is for the user to retire to a place of privacy and partially disengage the attachment ring, allowing the gas to escape. This is inconvenient and may occasionally cause inadvertent and undesirable spills; furthermore, it also risks unexpected complete separation of the attachment rings, with corresponding detachment of the pouch and probable spilling of its contents. In order to improve on this situation, various vents have been proposed for the pouch, usually in the form of an air filter of one type or another, often incorporating activated charcoal for absorbing odors, permanently or otherwise mounted over a vent opening located somewhere in the top portion of the pouch. Supposedly, such vent filters allow the interior of the pouch to continuously communicate with the exterior through the filter, such that any gas accumulation may automatically pass outward through the filter as function of pressure differentials. In actual practice, however, such filters have experienced substantial difficulty and lack of success, since they often become clogged from the materials inside the pouch, and thus rendered inoperative, leaving the user with no alternative but the old conventional one indicated above. In other instances, such filters have sometimes leaked fluid through them from the inside, causing obviously undesirable results, or else they have simply not been effective or reliable in permitting passage of the accumulated gas outwardly.
Accordingly, colostomy patients continue to experience the basic underlying difficulty and associated problems, giving rise to a continuing need for an ostomy pouch having a truly reliable and effective vent device.